ABSTRACT
Objective To evaluate the effect of inverse ratio ventilation (I ∶ E =1 ∶ 1) on ventilatory function during pneumoperitoneum in the obese patients undergoing laparoscopic surgery.Methods Sixty patients,aged 30-64 yr,of ASA physical status Ⅰ or Ⅱ],with body mass index of 30-40 kg/m2,scheduled for elective laparoscopic radical resection of rectal carcinoma,were divided into 2 groups (n =30 each) using a random number table:I∶E =1∶1 mode of ventilation after pneumoperitoneum (group A),and I∶E =1∶2 mode of ventilation after pneumoperitoneum (group B).Anesthesia was induced with midazolam,fentanyl,propofol and vecuronium.The patients were endotracheally intubated and mechanically ventilated.Anesthesia was maintained with infusion of propofol and remifentanil,sevoflurane inhalation,and intermittent iv boluses of vecuronium.In group A,the patients received I ∶ E =1 ∶ 1 after pneumoperitoneum.In group B,the patients received I ∶ E =1 ∶ 2.PaO2,PaCO2,peak inspiratory pressure (PIP),mean airway pressure (Pmean),dynamic compliance (Cdyn),intrapulmonary shunt (Qs/Qt),PETCO2,RR,MAP and HR were recorded immediately after intubation,and at 30,60 and 120 min of pneumoperitoneum.Results Compared with group B,PaO2,Pmean and Cdyn were significantly increased,and PIP and Qs/Qt were decreased,and no significant changes were found in RR,PET CO2,PaCO2 and hemodynamic parameters in group A.Conclusion Inverse ratio ventilation (I ∶ E =1 ∶ 1) can effectively improve ventilatory function during pneumoperitoneum in the obese patients undergoing laparoscopic surgery without exerting adverse effects on hemodynamics.